EarthTalk®

Dear EarthTalk: Is there any way to harness volcanic energy to meet our electricity and other power needs? — Antonio Lopez, Chino, CA

The short answer is yes: Heat generated by underground volcanic activity can and has been harnessed for electricity for over 100 years around the world. Utilities can capture the steam from underground water heated by magma and use it to drive the turbines in geothermal power plants to produce significant amounts of electricity. Getting at the sources is not so easy or cheap, though, as it requires drilling into unstable sections of the Earth’s crust and then harnessing the heat energy miles below the surface.

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Despite these difficulties, volcanic geothermal energy reserves account for about a quarter of Iceland’s energy consumption (with the rest taken up by another clean renewable resource, hydropower dams). According to statistics from the Geothermal Energy Association, the Philippines is also a big user of geothermal power: About 18 percent of that country’s electricity comes from underground volcanic sources. And in New Zealand, geothermal accounts for about 10 percent of total electricity consumption.

But believe it or not, the United States is actually the world’s largest producer of volcano-derived geothermal electricity, but still only derives less than one percent of its total power from such sources. California and Nevada are the leaders in this nascent form of renewable energy domestically, but promising efforts are also underway in Oregon, Utah, Alaska and Hawaii. Some analysts believe that the U.S. has enough geothermal capacity to provide 20 percent or more of the nation’s electricity needs.

Against the backdrop of diminishing oil reserves, tapping volcanic energy has become a high priority for some other regions as well. The war-ravaged East African nation of Rwanda is hoping to provide power for its people by harnessing the energy from volcanic gases at Lake Kivu, one of the continent’s largest lakes, covering some 1,000 square miles. The lake is one of three known “exploding” lakes subject to violent and sometimes deadly “overturns” triggered by volcanic activity. Methane and carbon dioxide from an adjacent volcano mix methane and carbon dioxide into the lake, making it a veritable tinder box, threatening the lives and homes of some two million people in the region.

In response to the risk—and also to produce energy—the Rwandan government has started using a large barge to suck up water and extract the methane gas therein. The methane is then used to fire the gas-powered Kibuye power plant. Already the system is producing 3.6 megawatts of electricity—some four percent of Rwanda’s total power supply. Within a few years, project backers hope to be generating between 50 and 100 megawatts of power from the operation. Extracting the methane also significantly reduces the risk of explosions, thus providing a measure of safety for area residents.

Humans have barely put a dent in the amount of power that can be captured from volcanic activity, but analysts expect to see much more of this form of power coming online over the next few decades. The U.S. Geological Survey refers to this phenomenon as the “plus side of volcanoes.” Environmentalists and others are hopeful that volcanic geothermal energy can become a major player in meeting a significant portion of our energy needs in our increasingly carbon-constrained world.

Dear EarthTalk: When we talk about “endangered species” we usually think of animal species, but someone recently told me that there was a worldwide crisis pertaining to the extinction of plants. Can you enlighten? — Max Blanchard, East Islip, NY

We may not realize it, but the health of the plant kingdom is crucial to the health of the planet and the animal life (which includes humans) it supports. “Through photosynthesis, plants provide the oxygen we breathe and the food we eat and are thus the foundation of most life on Earth,” reports the Center for Biological Diversity, an Arizona-based nonprofit dedicated to securing the future for endangered plants and animals throughout the world.

“Unlike animals, plants can’t readily move as their habitat is destroyed, making them particularly vulnerable to extinction,” says the Center. Habitat destruction—just one of the threats plants face—can lead to an “extinction debt” whereby even some plants that are plentiful now could disappear over time by being unable to disperse to new habitat patches. And global warming is already starting to exacerbate such problems. “With plants making up the backbone of ecosystems and the base of the food chain,” says the group, “that’s very bad news for all species, which depend on plants for food, shelter and survival.”

A 2009 report by the UK-based nonprofit, Plantlife, found that 15,000 of the 50,000 or so species of wild plants known for their medicinal qualities in traditional remedies are being overexploited and are potentially headed for extinction. The group says the fact that most people around the world—including some 80 percent of all Africans—rely on herbal medicines obtained primarily from wild plants underscores just how serious a problem a mass extinction of wild plants could be for humanity, let alone for the environment. Commercial over-harvesting does the most harm, though pollution, competition from invasive species and habitat destruction all contribute. “Commercial collectors generally harvest medicinal plants with little care for sustainability,” Plantlife reports, adding that shortages already exist in China, India, Kenya, Nepal, Tanzania and Uganda.

Another group, the International Union for the Conservation of Nature (IUCN), which compiles and maintains the famous “Red List” of endangered species around the world, found that a whopping 70 percent of the 12,000-plus plant species it has evaluated to date are threatened with extinction—despite the fact that each year about 2,000 new plants make themselves known to science. Of course, the organization only evaluates plants that are rare or have suffered major declines.

Meanwhile, researchers in the UK estimate that up to 33 percent of all flowering plants worldwide are threatened with extinction. “That percentage reflects the global impact of factors such as habitat loss,” says Lucas Joppa, the study’s lead author, who adds that climate change could increase the toll.

This worldwide threat to plants is just part of a larger biodiversity crisis, and the United Nations has declared 2010 “The International Year of Biodiversity” to raise awareness and encourage action to help stem the tide. The project’s website features listings of celebrations taking place around the world as well as resources for those who want to help spread the word and be part of the solution.